I noticed that when you add a post and then you delete it the miniavatars messes up. I'll explain it with this example (that is what happened to me):
Bolt_Head posts in a topic, so in the menu you can see Last Post by: Bolt_Head and you see his miniavatar (an high templar). Then I post, and I delete my post. When I come back to the menu it shows Last Post by Bolt_Head but with my miniavatar of the .scm map!
And an ask: can you get minerals posting, deleteing your post and posting again?